Hans Pfletschinger/Peter Arnold, Inc.
Most spider wasps are black, metallic blue, or reddish and measure from 1 to 5 cm (0.4 to 2.0 in) long. The wings range from clear to smoky-gray or bright red-orange in color. Their extraordinarily long hind legs distinguish spider wasps from other wasps. Spider wasps are usually seen walking on barren ground or in tangled undergrowth searching for prey. As they walk, their wings flicker and their antennae tap the ground. They often break their restless walking with short flights.
A spider wasp quickly subdues the spider it preys on. The wasp's sting affects the spider's central nervous system, paralyzing but not killing the spider. Often the spider is too large to carry in flight and the wasp must drag it to the nest. Some species bite off the spider's legs to make it easier to drag and may drink blood that leaks from the wounds. The spider wasp places a single spider in each nest, which is often constructed after catching the prey. Some species specialize on trap-door spiders and tarantulas, using the spider's own burrow for a nest. The wasp lays an egg on the paralyzed spider, which is eventually eaten by the wasp's larva.
The tarantula hawk is a large, metallic blue-black spider wasp, with violet or bright reddish-orange wings. Tarantula hawks are often seen foraging for nectar on milkweed flowers. These wasps enter a tarantula's burrow and may risk death in a fierce battle. The wasp usually wins even though the tarantula has poisonous fangs and is much larger than the wasp.
Scientific classification: Spider wasps comprise the family Pompilidae in the order Hymenoptera, which includes bees, ants, and other wasps. Tarantula hawks are in the genus Pepsis.